If a scene contains multiple cameras, which camera does the projectPoint method use to project points from 3D to screen-space? If this is defined by the pointOfView property, then how come when I update the position of the pointOfView a given 3D point is still projected to the same 2D point?
Since SCNCamera belongs to SCNView, just set the PoV via the "pointOfView" instance property of a View to a required camera node.
let cameraNode001 = SCNNode()
cameraNode001.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode001)
cameraNode001.position = SCNVector3(x: 0, y: 0, z: 15)
let cameraNode002 = SCNNode()
cameraNode002.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode002)
cameraNode002.position = SCNVector3(x: 10, y: 10, z: 30)
let sceneView = self.view as! SCNView
sceneView.scene = scene
sceneView.pointOfView = cameraNode001
then you can change PoV:
sceneView.pointOfView = cameraNode002
Related
I'm trying to generate a mesh from a depth/displacement map using SceneKit
The source depth map I'm using looks like this:
I then generate a plane with an increased segment count and heavily tessellate it and apply the displacement material. Here's the code I'm using:
import Cocoa
import SceneKit
import PlaygroundSupport
// MARK: - View setup
let scene = SCNScene()
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.camera?.zFar = 1000
scene.rootNode.addChildNode(cameraNode)
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light!.type = .omni
lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
scene.rootNode.addChildNode(lightNode)
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light!.type = .ambient
ambientLightNode.light!.color = NSColor.darkGray
scene.rootNode.addChildNode(ambientLightNode)
let scnView = SCNView(frame: NSRect(x: 0, y: 0, width: 400, height: 400))
scnView.autoenablesDefaultLighting = true
scnView.scene = scene
scnView.allowsCameraControl = true
scnView.showsStatistics = true
scnView.backgroundColor = NSColor.black
PlaygroundPage.current.liveView = scnView
// MARK: - Plane
let plane = SCNPlane(width: 200, height: 200)
plane.widthSegmentCount = 10
plane.heightSegmentCount = 10
let planeNode = SCNNode(geometry: plane)
planeNode.name = "Plane"
planeNode.geometry?.firstMaterial?.diffuse.contents = NSColor.white
let tessellator = SCNGeometryTessellator()
tessellator.tessellationFactorScale = 25
tessellator.tessellationPartitionMode = .pow2
tessellator.insideTessellationFactor = 4
tessellator.edgeTessellationFactor = 4
tessellator.smoothingMode = .phong
planeNode.geometry?.tessellator = tessellator
planeNode.geometry?.firstMaterial?.displacement.contents = "rabbit"
planeNode.geometry?.firstMaterial?.displacement.textureComponents = .red
planeNode.geometry?.firstMaterial?.displacement.intensity = 200
planeNode.geometry?.firstMaterial?.displacement.maxAnisotropy = 1
planeNode.geometry?.firstMaterial?.displacement.magnificationFilter = .none
planeNode.geometry?.firstMaterial?.lightingModel = .phong
scene.rootNode.addChildNode(planeNode)
Which mostly gives me the 3D mesh I'm aiming for:
But the resulting "blockiness" messes with the lighting. Wireframe view shows it clearer:
Is there any way to "smoothen" the resulting mesh, average vertex positions, or something similar?
I'm very tangentially familiar with 3D and basically unfamiliar with SceneKit and google/docs haven't yielded much.
Subdivision / adaptive subdivision doesn't solve the problem, neither does increasing tessellation detail to the highest count possible. It can make the shadow/highlight patches smaller, but they're still there.
Any help or pointers are much appreciated!
I figured it out!
The ladder effect is an artifact of 8-bit banding in the depth map
Converting the image to 32-bit depth and adding a slight blur pretty much fixed it:
How can I enable the user to move the object using the right and left arrows I put below, instead of manually moving it?
"allowscameracontrol" allows the user to rotate the object with their hand. But I just want it to be rotated using arrows.
** -> sceneView.allowsCameraControl = true**
import UIKit
import SceneKit
class ViewController: UIViewController {
#IBOutlet weak var sceneView: SCNView!
override func viewDidLoad() {
super.viewDidLoad()
// 1: Load .obj file
let scene = SCNScene(named: "converse_obj.obj")
//Add camera node
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
//Place camera
cameraNode.position = SCNVector3(x: 0, y: 10, z: 35)
//*Set camera on scene
scene?.rootNode.addChildNode(cameraNode)
//Adding light to scene
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light?.type = .omni
lightNode.position = SCNVector3(x: 0, y: 10, z: 35)
scene?.rootNode.addChildNode(lightNode)
// 6: Creating and adding ambien light to scen
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light?.type = .ambient
ambientLightNode.light?.color = UIColor.darkGray
scene?.rootNode.addChildNode(ambientLightNode)
// Allow user to manipulate camera
sceneView.allowsCameraControl = true
// Set background color
sceneView.backgroundColor = UIColor.white
// Allow user translate image
sceneView.cameraControlConfiguration.allowsTranslation = false
// Set scene settings
sceneView.scene = scene
}
}
I haven't used SceneKit before.
I'm not sure if you would want to rotate your camera or rotate the node that contains the object. From the way it's named, it makes it sound like allowsCameraControl rotates the camera. In any case you would use rotationMatrixAroundZ to create a rotation matrix, and then multiply that by the matrix for whichever thing you want to rotate.
If rotating the camera is what you want to do, your code might look like this:
func rotateCameraZByDegrees(_ zRotation: Double) {
let radians = zRotation / 180.0 * Double.pi
let rotationZ = rotationMatrixAroundZ(radians: radians)
cameraNode.transform = SCNMatrix4(simd_mul(simd_float4x4(cameraNode.transform), rotationZ))
}
If you instead want to rotate your object's node, and your object's node is named sneakersNode, change the last line to:
sneakersNode.transform = SCNMatrix4(simd_mul(simd_float4x4(sneakersNode.transform), rotationZ))
This post [31881911] in stackO shows you some examples for arrow keys.
Turn allowsCameraControl = false
This post [68506605] see my answer - creating a camera control class makes things a lot easier.
For your rotation, just rotate the object directly - several ways to do this.
func resetRotation()
{
for (_, vNode) in displayNodes
{
vNode.node.removeAllActions()
}
vRotate0 = SCNAction.rotateTo(x: 0, y: 0, z: 0, duration: 2)
vRotate1 = SCNAction.rotateBy(x: 0, y: CGFloat(GLKMathDegreesToRadians(450)), z: 0, duration: 3)
vRotate2 = SCNAction.rotateBy(x: 0, y: CGFloat(GLKMathDegreesToRadians(-90)), z: 0, duration: 1)
vRotate3 = SCNAction.rotateBy(x: CGFloat(GLKMathDegreesToRadians(-45)), y: 0, z: 0, duration: 1)
vRotate4 = SCNAction.rotateBy(x: CGFloat(GLKMathDegreesToRadians(45)), y: 0, z: 0, duration: 1)
seq = SCNAction.sequence([vRotate0, vRotate1, vRotate2, vRotate3, vRotate4, vRotate3, vRotate4])
allSeq = SCNAction.repeatForever(seq)
for (_, vNode) in displayNodes
{
vNode.node.runAction(allSeq)
}
}
You could use some sequences - so your object could do a 360 and stop, come back 90 at a slower pace, whatever you want. The above repeats forever, but you can take that out.
Or just on Left key press, rotate Y += n degrees.
I want to limit the angle of the camera in Scenekit to not allow the camera to look upwards (point to the sky). For some reason I am not getting the SCNTransformConstraint right. What to do?
let cameraNode = SCNNode()
let camera = SCNCamera()
cameraNode.camera = camera
cameraNode.position = SCNVector3(x: 0, y: 10, z: 30)
let center = SCNNode()
center.position = SCNVector3Make(15, 0, 10)
let lookConstraint = SCNLookAtConstraint(target: center)
lookConstraint.isGimbalLockEnabled = true
// Make the constraint to not allow the camera to point upwards
let transformConstraint = SCNTransformConstraint(inWorldSpace: true, with: {
node, matrix in
var newMatrix = matrix
let currentNode = node as SCNNode
if (currentNode.presentation.eulerAngles.x > 0) {
newMatrix.m31 = 0.0
}
return newMatrix
})
cameraNode.constraints = [lookConstraint, transformConstraint]
scene.rootNode.addChildNode(cameraNode)
I guess I am setting the newMatrix.m31 incorrectly?
The documentation in XCode clearly states that hitTesting a geometry in SceneKit can be done with SCNRender, SCNView or the SCNNode themselves when one plans to test a 3D line segment. I have a use for SCNScene with its nodes without a renderer or a view, therefore I am planning to use SCNNode hitTesting. I create a SCNScene, put a SCNNode in it and test a simple ray that goes through, but I always get an empty hitList and I don't understand why:
import Swift
import SceneKit
let boxGeometry = SCNBox(width: 1.0, height: 1.0, length: 1.0, chamferRadius: 0)
let boxNode = SCNNode(geometry: boxGeometry)
var scene = SCNScene()
scene.rootNode.addChildNode(boxNode)
let from = SCNVector3(x: 0, y: -2, z: 0)
let to = SCNVector3(x: 0, y: 2 , z: 0)
var hits = scene.rootNode.hitTestWithSegmentFromPoint(from, toPoint: to, options:nil) // this is always empty
if hits != nil {
if hits!.count > 0 {
var hit = (hits!.first as! SCNHitTestResult).node as SCNNode
}
}
I have tried passing various forms of options but nothing changes.
SCNHitTestFirstFoundOnlyKey: yes or no does not change anything
SCNHitTestSortResultsKey: yes or no does not change anything
SCNHitTestClipToZRangeKey: invalid for SCNNode
SCNHitTestBackFaceCullingKey: yes or no does not change anything
SCNHitTestBoundingBoxOnlyKey: yes or no does not change anything
SCNHitTestRootNodeKey: rootNOde of scene or boxNode does not change
anything
SCNHitTestIgnoreHiddenNodesKey: yes or no does not change anything
What am I doing wrong?
I have found the answer, which is either a bug or a feature: using SCNScene and its nodes SCNNode for 3D hitTesting, in particular the method: "hitTestWithSegmentFromPoint(toPoint:options:)" does not return a hit unless the scene is included in an SCNView. It appears it cannot be used offscreen. My guess is yours for why this is the case, although I can imagine it has something to do with performing some of these quite expensive calculations on the graphics card.
I have tested this using the GameView SCNScene starter project. The critical line is self.gameView!.scene = scene
override func awakeFromNib(){
let scene = SCNScene()
let boxGeometry = SCNBox(width: 1.0, height: 1.0, length: 1.0, chamferRadius: 0.0)
let boxNode = SCNNode(geometry: boxGeometry)
boxNode.position=SCNVector3(x: 0, y: 0, z: 0)
scene.rootNode.addChildNode(boxNode)
// create and add a camera to the scene
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode)
// place the camera
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
// create and add a light to the scene
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light!.type = SCNLightTypeOmni
lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
scene.rootNode.addChildNode(lightNode)
// create and add an ambient light to the scene
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light!.type = SCNLightTypeAmbient
ambientLightNode.light!.color = NSColor.darkGrayColor()
scene.rootNode.addChildNode(ambientLightNode)
// set the scene to the view
// uncomment this to fail
self.gameView!.scene = scene
// allows the user to manipulate the camera
self.gameView!.allowsCameraControl = true
// show statistics such as fps and timing information
self.gameView!.showsStatistics = true
// configure the view
self.gameView!.backgroundColor = NSColor.blackColor()
let hitList = scene.rootNode.hitTestWithSegmentFromPoint(SCNVector3(x:-10,y:0,z:0), toPoint: SCNVector3(x:10,y:0,z:0), options:[SCNHitTestBackFaceCullingKey:false, SCNHitTestSortResultsKey:true, SCNHitTestIgnoreHiddenNodesKey:false])
if hitList?.count > 0 {
println("Hit found: \n\n\( hitList![0] )") // assign self.gameView!.scene = scene to reach this point.
} else {
println("No hit") // uncomment self.gameView!.scene = scene to reach this point.
}
}
I've also had trouble with hitTestWithSegmentFromPoint.
I was calling it in viewDidLoad() and it returned a 0 elements array, though I was sure there was a hit.
Calling it in viewDidAppear() (or later) solved my problem.
I am getting my feet wet with iOS SceneKit, however the following sample code (which executes inside viewDidLoad) is not behaving as expected. I want it to
place a camera at origin with direction of view towards positive z axis
place a red rectangle parallel to xy-plane at z = 100
Why does the rendering not reveal the red rectangle but only a black screen?
let scene = SCNScene()
// prepare camera
let camera = SCNCamera()
camera.zNear = 90
camera.zFar = 110
let cameraNode = SCNNode()
cameraNode.position = SCNVector3Make(0, 0, 0)
cameraNode.rotation = SCNVector4Make(1, 0, 0, Float(M_PI))
cameraNode.camera = camera
scene.rootNode.addChildNode(cameraNode)
// prepare light
let light = SCNLight()
light.type = SCNLightTypeOmni
light.color = SKColor(white: 0.3, alpha: 1.0)
let lightNode = SCNNode()
lightNode.light = light;
scene.rootNode.addChildNode(lightNode)
// prepare plane
let plane = SCNPlane(width: 400, height: 400)
plane.firstMaterial!.doubleSided = true
plane.firstMaterial!.diffuse.contents = UIColor.redColor().CGColor
let planeNode = SCNNode(geometry: plane)
planeNode.position = SCNVector3Make(0, 0, 100)
scene.rootNode.addChildNode(planeNode)
// prepare view as SCNView
let sceneView = view as SCNView
sceneView.backgroundColor = SKColor.blackColor()
sceneView.scene = scene
sceneView.delegate = self
sceneView.jitteringEnabled = true // i.e. improve visual rendering
sceneView.pointOfView = cameraNode
looks like you rotate around the x axis instead of the y axis (so that the camera looks in the desired direction)